You could try a code block in the field calculator.
def dd_mm_ss(dd, cal_long=True, use_sign=True, use_quad=True):
"""decimal degrees to deg dec min"""
deg_sign = u'\N{DEGREE SIGN}'
deg = int(dd)
if deg < 0:
quad = ['S', 'W'][cal_long]
deg = abs(deg)
else:
quad = ['N', 'E'][cal_long]
if not use_quad:
quad = ""
if not use_sign:
deg_sign = ""
mins, secs = divmod(dd*3600, 60)
degs, mins = divmod(mins, 60)
frmt = "{}{} {:0.0f}' {:05.2f}{}''".format(deg, deg_sign, mins, secs, quad)
return frmt
dd_mm_ss(!YourField!, True, True, True)
yielding
dd_mm_ss(-75.5, True, True, True)
"75° 30' 00.00W''"
Of course, there are variants and you can mess with the code to suit your needs